Answer :

luana
[tex] \left \{ {{5x+4y=8} \atop {x-2y=10\ |\cdot2}} \right. \\\\ \left \{ {{5x+4y=8} \atop {2x-4y=20}} \right. \\+-----\\\\7x=28\ \ \ \ |:7\\x=4\\\\4-2y=10\\-2y=10-4\\-2y=6\ \ \ \ \ |:-2\\y=-3\\\\ \left \{ {{y=3} \atop {x=4}} \right. [/tex]